Light emitting diode (LED) lighting systems are becoming prevalent as replacements for older lighting systems and are used in many other applications. LED systems are an example of solid state lighting (SSL) and have advantages over traditional lighting solutions, such as incandescent and fluorescent lighting, because they use less energy, are more durable, operate longer, and generally contain no lead or mercury. A solid-state lighting system may take the form of a lighting unit, light fixture, light bulb, or a lamp. An LED lighting system may include, for example, a packaged light emitting device including one or more light emitting diodes (LEDs), which may include inorganic LEDs, which may include semiconductor layers forming p-n junctions and/or organic LEDs, which may include organic light emission layers.
LEDs may generate light in a wide variety of colors and can be combined in multi-color arrays that can be controlled to deliver virtually any color light including light perceived as white or near-white. Output color of such a device may be altered by separately adjusting the supply of current to different color LEDs.